ACE2 is a major receptor for cellular entry of SARS‐CoV‐2. Despite advances in targeting ACE2 to inhibit SARS‐CoV‐2 binding, strategies to flexibly and sufficiently reduce ACE2 levels for the prevention of SARS‐CoV‐2 infection have not been explored. Here, we reveal vitamin C (VitC) administration as a potent strategy to prevent SARS‐CoV‐2 infection. VitC reduces ACE2 protein levels in a dose‐dependent manner, while even a partial reduction in ACE2 levels can greatly inhibit SARS‐CoV‐2 infection. Further studies reveal that USP50 is a crucial regulator of ACE2 levels. VitC blocks the USP50‐ACE2 interaction, thus promoting K48‐linked polyubiquitination of ACE2 at Lys788 and subsequent degradation of ACE2 without affecting its transcriptional expression. Importantly, VitC administration reduces host ACE2 levels and greatly blocks SARS‐CoV‐2 infection in mice. This study reveals that ACE2 protein levels are down‐regulated by an essential nutrient, VitC, thereby enhancing protection against infection of SARS‐CoV‐2 and its variants.
Rheumatoid arthritis (RA) is an autoimmune disease with nearly 1.6 billion patients worldwide and an incidence of 0.5−1%. In recent years, basic and clinical studies have revealed that immune cell responses and corresponding secretion of inflammatory factors are important in the control of RA development. Our study found that a natural plant ingredient, menthone, could be used as a potential antirheumatism compound. In vivo observations demonstrated that menthone alleviates collagen II-induced arthritis (CIA) in mice. Furthermore, we found that menthone regulates the number of Th1 and Th17 cells in CIA mice. Importantly, menthone significantly inhibits the release of proinflammatory cytokines, including TNF-α, IL-1β, and IL-6, in CIA mice. Our study suggests a potential component for the development of drugs to treat rheumatoid arthritis.
Freund's complete (FCA) and incomplete adjuvants (FIA), generally applied in subunit fishery vaccine, have not been explored on the molecular mechanism of the nonspecific immune enhancement. As long noncoding RNAs (lncRNAs) play vital regulating roles in various biological activities, in this study, we examined the genome-wide expression of transcripts in the liver of European eel (Anguilla anguilla, Aa) inoculated with FCA and FIA (FCIA) to elucidate the regulators of lncRNAs in the process of Edwardsiella anguillarum (Ea) infection and Aa anti-Ea infection using strand specific RNA-seq. After eels were challenged by Ea at 28 d post the first inoculation (dpi), compared to the control uninfected eels (Li group), the control infected eels (Con_Li group) showed severe bleeding, hepatocyte atrophy and thrombi formed in the hepatic vessels of the liver, although eels inoculated with FCIA (FCIA_Li group) also formed slight thrombi in the hepatic vessels. Compared to the FCIA_Li group, there was about 10 times colony forming unit (cfu) in the Con_Li group per 100 µg liver tissue, and the relative percent survival (RPS) of eels was 50% in FCIA_Li vs Con_Li. Using high-throughput transcriptomics, differential expressed genes (DEGs) and transcripts were identified and the results were verified using fluorescence real-time polymerase chain reaction (qRT-PCR). Interactions between the differential expressed lncRNAs (DE-lncRNAs) and the target DEGs were explored using Cytoscape according to their co-expression and co-location relationship. We found 13499 lncRNAs (10176 annotated and 3423 novel lncRNAs) between 3 comparisons of Con_Li vs Li, FCIA_Li vs Li and FCIA_Li vs Con_Li, of which 111, 110 and 129 DE-lncRNAs were asertained. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of DEGs targeted by DE-lncRNAs revealed these DEGs mainly involved in single-organism cellular process in BP, membrane in CC and binding in MF, and KEGG pathways showed that the target DEGs in co-expression and co-location enriched in cell adhesion molecules. Finally, 118 DE-lncRNAs target 1161 DEGs were involved in an interaction network of 8474 co-expression and 333 co-location related links, of which 16 DE-lncRNAs play vital roles in anti-Ea infection. Taken together, the interaction networks revealed that DE-lncRNAs underlies the process of Ea infection and Aa anti-Ea infection.
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